Calcitriol (1,25-Dihydroxyvitamin D) Test
This test measures calcitriol, the bioactive form of vitamin D known as 1,25-dihydroxyvitamin D, in a blood sample. It is used in the differential diagnosis of hypocalcemia and to monitor certain kidney-related conditions.
About this test
Calcitriol, or 1,25-dihydroxyvitamin D, is the bioactive form of vitamin D. This test is used in the differential diagnosis of hypocalcemia and to monitor patients with renal osteodystrophy or chronic renal failure.
The sample is 0.6 mL of serum, analyzed using chromatography/mass spectrometry. Because this test measures a different form of vitamin D than the standard deficiency screen, a clinician chooses between them based on what is being evaluated.
Test details
| Quest code | 16558 |
|---|---|
| Methodology | Chromatography/Mass Spectrometry |
| Sample type | 0.6 mL serum |
| Collection | Quest patient service center |
Related tests and panels
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Additional details
What this test looks at
The test reports one value: 1,25-dihydroxyvitamin D (calcitriol) in serum, along with its two component forms, vitamin D2 and vitamin D3, in the 1,25-dihydroxy form. Quest lists this test under several related aliases, including 1,25 OH-D, 1,25 Dihydroxyvitamin D, and Dihydroxycholecalciferol.
How it's often used alongside other tests
Because calcitriol is not suitable for diagnosing vitamin D deficiency or monitoring supplementation, it is ordered for different reasons than a standard 25-hydroxyvitamin D test, most often alongside calcium and kidney-function markers when a clinician is evaluating hypocalcemia or a kidney-related condition.
Order online and a physician order is included — no doctor's visit and no insurance needed. Your sample is collected at a Quest Diagnostics patient service center.
Laboratory results should always be interpreted by a licensed clinician who knows your health history. This page is information about a test, not medical advice.
Frequently asked questions
What does this test measure?
It measures calcitriol, also called 1,25-dihydroxyvitamin D, the bioactive form of vitamin D, in a serum sample using chromatography/mass spectrometry.
How is the sample collected?
The test uses a 0.6 mL serum sample collected through a routine blood draw.
Do I need to prepare for this test?
No preparation instructions are listed for this test, though people follow any instructions their ordering clinician provides.
Is this the right test to check my vitamin D level?
Not for a standard deficiency check. This test is not suitable for diagnosing vitamin D deficiency or monitoring supplementation; the 25-hydroxyvitamin D test is the recommended test for those purposes instead.
Why might this test be ordered?
It is used in the differential diagnosis of hypocalcemia and to monitor patients with renal osteodystrophy or chronic renal failure.
Can I get the Vitamin D 1,25 test without a doctor's visit or insurance?
Yes. The $215 cash price includes an independent physician's order, so no referral is needed, and insurance is never involved.